Switch contact



June 29, 1937. w. J. SHORE SWITCH CONTACT Filed March 28, 1935 3 Sheets-Sheet 1 INVENTOR.

i v W g 3?? ATTORNEYS w. J. SHORE 2,085,707

SWITCH CONTACT June 29, 1937.

Filed March 28, 1935 I /III// l I n INVENTOR.

I/IIIIIIIIIIIIIIIIIII 11111111, v I/Illl/A ATTORNEYS June 29, 1937. w. J. SHORE 2,085,707

SWITCH CONTACT Filed March 28, 1935 3 Sheets-Sheet 3 I N VENTOR.

PULL/21 JJHo/as. BY 7 ATTORNEYS Patented June 29, 1937 UNITED STATES PATENT. OFFICE '7 Claims.

My invention relates to switch-contacts for making electric contact betweentwo parts, one of which may be stationary and the other removable, such, for example, as the contacts or contact surfaces for knife, plug or fuse switches or ing a tight contact even though the parts be displaced or become worn.

In the switches, as heretofore constructed, the yielding. parts have yielded in on ly one direction or about a single pivot; consequently if the member that is brought into contact or inserted between'the yielding elements becomes displaced or twisted in a direction other than that provided for by the yielding of the contact elements, the

2o closeness or tightness of contact will be impaired and a large part of the contact surface may be" spaced from or diverge from the yielding elements. In such cases the resistance through the switch element is greatly increased reducing its efficiency and creating heat which causes rapid deterioration.

In switches of the above type an arc tends to form as the removable element is withdrawn. In switches heretofore constructed this are tends to form between the contact surfaces resulting in pitting or building up of deposits which impair the contact surface and increases the resistance through the switch contacts.

These'various disadvantages are avoided in my present invention which provides yielding contact surfaces that yield inseveral directions so as to adapt themselves tov'arious displacements of the movable contact element, and which also shift the point of departure of the removable contact when being withdrawn from the fixed contact surface so as to displace the arc to surfaces other than the contact-making surfaces. y

Various features of the invention are illustrated in the accompanying drawings in which 5Fig. 1 is a longitudinal section showing half of a contact switch of the plug type embodying a. preferred form of the invention; Fig. 2 is a longitudinal sectional view..taken at a right-angle to the view of Fig. 1; Fig. 3 is a cross-section on the 50 line 3 -3 of Fig. 2; Fig. 4 is a perspective view of a pair of plug-receiving contact elements; Fig. 5 is a plan view of a blank from which the contact-receiving elements of Fig. 4 may be formed; Figs. 6 and! are detail sectional views 55 similar to that of Fig. 2 and on an enlarged scale switch embodying the-invention: Fig. 19 is a showing the displacement of contact as the contact element is inserted and removed from between the receiving contacts; Fig. 8. is an enlarged detail side view of a portion of a contact embodying my invention; Fig. 9 is an enlarged longitudi- 5 nal section taken on a 'plane similar to that of Fig. 2 and showing the yielding of the contact elements to adjust themselves to displacements of a plug from its normal position between the contact surfaces; Fig. 10 is a cross-section similar 10 to that of Fig. 3 on an enlarged scale showing the normal displacement of the contact surface upon insertion of a plug in proper position; Fig. 11 is a view similar to Fig. 10 but showing the twisting of the contact blades to adjust themselves to a 16 displacement of the plug from its normal posi-. tion; Figs. 12, 14, 15 and -Figs..-13, 16 and 1'? are vertical side elevations and horizontal cross-sections of various modifications of the contactsurface elements; Fig. 18 is a side view of a knife vertical section of the knife switch taken on line l9-l9 of Fig. 18; Fig. 20 is aview similar to that of Fig. 19 of a different embodiment of the invention; Fig. 21 is a plan of a blank from which-the contact element of Fig. 19 may be stamped; Fig.

v 22 is a plan of a blank from which the switch plate from which-they are stamped, preferably at an edge transverse to the direction in which. 40 the knife or plug is to be inserted so that they ma swingabout this edge as a pivot. The wings are rounded or curved convexly toward the inserted knife or plug so as to present a tangent surface to the latter in various positions of displacement ofthe wings. The wings are also narrowed somewhat at the edge where they join the supporting strip fromwhich they are pressed so that they may twist or deflect slightly on an axial line parallel or longitudinal'to the, line of insertion of the blade or plug. Consequently any sidewise displacement or tilting ofthe blade or v V plug on a line transversE-to itsilengthl-will be accommodated by a springing= lnwardlymorouts wardly of the several wings-and anytwistingfor u axis is accommodated by a slight twisting of the wings, it being understood that these wings tend to take the normal position but are readily displaceable therefrom against their spring action by the plug or blade.

Several such wings are provided upon each contact surface or contact-receiving element so that a large number of tangent contacts may be made. Normally the wings tend to swing away from their point of support and as the blade or plug is swung into contact they are displaced. As the blade leaves the contact the wings tend to close over the end-edge so that the last contact is nearer to the base of the wings than their contact surface "and the arc tends to form at this point rather than at the contact-making surfaces of the wings.

Referring more particularly to Figs. 1 to 5 of the drawings, the invention is shown as applied to a common type of socket and plug connection, such as is used for flat irons and similar purposes. I a

In this embodiment, a pair of contact blades I and 2 are mounted in a plug 3, preferably formed in two halves, bolted together by means of a bolt I and containing binding posts 5 and 6 to connect the blades I and 2 respectively to the wires of a cable I. The blades I and 2 project from the end of the plug 3 and are insertable in recesses 6 and 9 of a socket element In which also may be formed of a pair of halves joined by bolts I I. Each of the recesses 8 and 9 is provided with a pair of contact-receiving plates I2 of identical construction and arranged in opposed or mirror image relation as shown in Figs. 2 and 4. The plates I2 are joined at their upper end I3 I 2 or and are secured at this end by means of a binding screw I4 which connects them. to the wires of a cable I5.

As shown in the above figures, and also in larger scale in Figs. 6 to 11 inclusive, each of the contact plates or elements I2 is provided with a number of wings I6 which project inwardly toward each other so as to grip blades I and 2.

The wings I6 are curved convexly toward the blade I and normally extend toward each other to a distance less than the thickness of the blade, as indicated in Fig. 6. When the blade I is inserted the wings are spread apart against their tension and thus form a resilient close sliding contact with the sides of the inserted blade. The position of contact varies with the thickness of the blade, but in all displacements of the blade it occurs at the rounded surface of the wing so that ol or close contact throughout.

there is at all times 'a tangent contact.

Inasmuch as there are several wings for each receiving contact, a relativelylarge aggregate area or line is provided while still preserving a line or tangent contact therebyinsuring a tight This would be much more dimcult, if not impossible, if it were attempted by a single continuous line contact.

It will be noted, moreover, that the normal contact line when the blade is inserted is at the level XX, Fig. 7, but as the contact is displaced and the blades gradually close'the level of contact lowers to that of Fig. 6, or even lower, and the blade is separated from the wings at the lower level indicated in Fig. 6.- Any arcing that may take place is, therefore, at this lower level and away from the normal contact surface so that the latter is preserved from pitting or burning or deposition of metal.

In order to strengthen the supporting surface of thecontact plates I 2 from which the wings I6 warping of the blade or plug about alongitudinal diverge, the edges of these wings are offset as at IT thereby forming in effect a channel or Z-shaped construction at each edge of the elements I2 between the intermediate part I6 that connects these channel elements between the wings.

The transverse width of the wings I6 at their base where they join the intermediate part It is of a dimension not exceeding the width of the intermediate part I8 and preferably somewhat less; whereas the free part of the wings is wider havingbeen formed from metal of the displaced part I! before the displacement of the latter. This maybe accomplished by stamping the contact elements I2 from a blank, such as that shown in Fig. 5, in which trapezoid cuts are formed for the wings I6 and the offset part II is thereafter formed by bending on the longitudinal lines I9 and 20, the line I9 being at the base or narrow dimension of the trapezoid and the line 26 at its wider point.

The part of the stamp between the pair of contact surfaces I2 is narrowed to form the neck portions 2I and 22 which may be folded on the transverse line 23 tobring the parts I2 into opposed position, the blank being also bent or offset on the lines 24 and 25 to provide the proper spacing. The neck portions 2I and 22 are provided with openings 26 which align when the blank is bent on the line 23, and the neck 22 is provided with side flanges 21 that form the en-- By having the base part of the wing I6 nar- -rowed, it is given a limited flexibility in a transverse direction so that it may twist to accommodate itself to the warping or twisting of the blade In this way the wings may accommodate themselves to sidewise warping or twisting as well as to displacements sidewise or inclined to their true or proper longitudinal position. This is illustrated in Figs. 9, 10 and 11.

Fig. 9 shows the accommodation of the wing I6 to contact with opposite surfaces of the blade I inserted in a position slightly oblique to the longitudinal. At the lower part of the contactreceiving socket the wing is displaced still further from its normal contact position, but this has only the effect to slightly lower the line of tangent contact to the position shown by the dotted line 29. The opposite wing is not pressed back as far, and the tangent line will be at 30. The intermediate wings hit the blade at about the normal position and the upper wings are displaced in the opposite sense from the lower, the right-hand contact line 3| being lower than the left-hand contact line 32. The accommodation of the wings to twisting or warping is shown in Figs. 10 and 11, in which Fig. 10 shows the normal position of the blade I and the normal displacement of the.

wings I6; whereas Fig. 11 shows, in somewhat exaggerated maner, the effect of a sidewise warping which is accommodated by a twisting of the wings I6.

Figs. 12 and 13 show a still further modification of the wing construction in which the offset is obtained in the modification shown in Fig. 14

by the sidewise slits 34 which narrow the point or area of twisting.

to that of Figs. 1 to 11 exceptthat instead of having an offset I! or a Z or channel or flange construction, the edges are bent inwardly as at 31 to enclose the wings and plates. This has the advantage of spacing the wings and their supporting plates at a proper pre-determined position.

Figs. 18, 19 and 20 show an embodiment of the invention as applied to a knifeswitch. In this .constructionthe contact blade 38 is pivoted at one end to an upright 39 mounted on an insulating base 40. The blade is movable on the pivot 39 by .means of an insulating handle so as to bring it between a pair of contact terminals or plates 42 and 43 from which the wings l8 spring inwardly, as described in previous modifications. i v 'I'he plates 42 and 43 are reinforced and strengthened against sidewise displacement by means of sidewise abutments 44 and 45. In the modification shown in Fig. 19 these abutments are formed from a stamping having the trapezoidal cuts to form the wings I6 and shaped to provide a base 45 from which the plates are bent on lines 41 and 48, and from the latter the reinforcements or abutments 44 and 45 are bent on lines 49 and 50.

A stop 5| for the blade 38 is provided by bending in a tongue from one end-ofthe plate 42.

In the modification shown in Fig. 19 the plates 42 and 43 are secured by a bolt 52 in the base 45. The modification shown in Fig. 20 differs in that the contact elements are secured by a pair of bolts 53. These boltsfasten in ears 54 bent from the sidewise abutments 44 and 45.

Fig. 23 shows the invention as applied to a fuse 55 having end contact plates 55 and 51 that are'insertable between terminal elements 58 and 59 respectively, similar in construction to those shown in Figs. 19 and 20 but differing only in that they are secured to the base 60 by means of bolts 5| passing through a. sidewise extension 62 from the base 46.

By the above invention, therefore, I have provided a. contact device in which a contact-making surface may be deflected in a transverse direction and may also twist to accommodate itself to deflection or warping in the terminal with which it is to make contact.

The invention. also provides a number of tangent or line contacts in all positions of the Moreover, the

wings to said plate:

readily and easilyformed by simply cutting and stamping a piece of sheet metal and, therefore,

' provide a very inexpensive construction.

What I claim isv 1. A contact having a space into which a contact blade maybe inserted and a contact plate in said contact having wings integral with and sprung from the face of said plate toward a position of contact with an insertedblade, said wings being convex toward said blade and spaced at successive intervals along the direction of inertion of said blade.

2. Acontact having a space into which a contact blade may be inserted and a contact plate in said contact having a succession of parallel wings sprung from the surface of said plate toward a position to contact with an inserted blade,

said wings being integral with said plate at one I oftheir edges and being convex toward an inserted blade and spaced at successive intervals 'vex toward such inserted blade and spaced at successive intervals along the direction of inertion of said blade.

4. A contact having a space into which a con tact blade may be inserted and having a metallic plate facing said space, said metallic plate having wings of trapezoid shape, cut and stamped therefrom with the smaller of the parallel edges of said wings integral with said plate, said wings being convex toward a blade inserted into said space.

5. A contact havinga space into which a contact blade may be inserted and having a metallic plate facing said space, said plate having its side edges flanged toward said space and having integral wings sprung from a face of said plate into a position to contact with an inserted blade, said wings being convex toward an inserted blade. I

6. A contact having a space into which a contact blade may be inserted, a pair of spaced plates stamped from a single sheet bent to space said plates on opposite sides of said blade receiving space, said plates having contact wings sprung from the opposed surfaces to a position to contact with'said inserted blade, said wings being integral with said plates at one of the edges of the respective wings and being convex to the inserted blade and spaced at successive intervals along the direction of inertion of said blade.

'7. A contact having a space into which a contact blade may be inserted and having a metallic plate facing said space, wings stamped from said plate and integral at one edge therewith and convex to an inserted blade,.said wings having slots extending from the sides of the wings at said integral edge toward the center lines of said wings to narrow the connection of said WILLIAM J. SHORE. 

